1. Field of the Invention
The invention relates to a block copolymer containing one or more blocks of a perfluoroether polymer and one or more blocks of a polymer made from selected vinyl monomers, the blocks being connected by specified groups. The copolymers of the present invention are useful for surface property modification.
2. Background Art
Y. Oshibe, et al., European Patent Application 0,161,804 disclose block copolymers of a fluorine containing vinyl monomer block and a fluorine free vinyl monomer block, using certain peroxy or azo group containing free radical initiators. No mention is made of perfluoroether polymer blocks.
Telechelic perfluoroether polymers containing polymerizable acrylic end groups are disclosed by D. E. Rice and J. V. Ihlenfeld in U.S. Pat. No. 4,440,918. When the acrylic end groups are polymerized, the perfluoroether polymer segments form crosslinks (branches) between acrylic polymer chains. Thus the perfluoroether polymer segments are not part of the "main" acrylic polymer chain formed by the reactive end groups.
There are several disclosures of polymers containing perfluoroether polymer side chains, made from polymerizable monomers containing these perfluoroether polymer groups. For example, G. Caporiccio and E. Strepparola in U.S. Pat. No. 3,766,251 disclose acrylic polymers containing side groups of poly(hexafluoropropylene oxide) and/or poly(tetrafluoroethylene oxide). The perfluoroether polymer segments are not part of the (acrylic) main polymer chain.
A similar disclosure is made by A. Ohmori, et al., U.S. pat. No. 4,655,807, where poly(hexafluoropropylene oxide) polymers are attached to acrylic polymers as a side chain through the acrylic ester linkage.
U.S. Pat. Nos. 3,810,875 and 3,882,193 describe block copolymers comprising at least one block derived from at least one free radical polymerizable terminally unsaturated monomer and at least one block comprising poly(perfluoroalkylene oxide). Although the connecting group between blocks is not stated, it is believed from the chemistry of the reactions used to make these block copolymers that the connecting linkage is a covalent bond.